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1864: Difference between revisions
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==Internals== | ==Internals== | ||
The 1864 is solid-state except for the test voltage supply pass element, a 6AB4 (EC92) vacuum tube. | The 1864 is solid-state except for the test voltage supply pass element, a 6AB4 (EC92) vacuum tube. | ||
Current through the unknown is converted to a voltage using decade reference resistors from 2 kΩ to 2 GΩ. In the highest range (10 TΩ multiplier), feedback is used to multiply the effective reference resistance by a factor of 10. | |||
A four-stage, FET-input amplifier drives an analog meter. | |||
==Photos== | ==Photos== | ||